Multi-Image projection onto a common screen is widely practiced, using a plurality of slide projectors of like configuration. The projectors employed are electrically automated and each is self contained and characterized by a magazine containing a large number of transparencies or slides to be projected onto the screen; a typical configuration being that of the carousel type wherein a circular magazine is superimposed upon a rectangular box-shaped housing. The projector housing is more or less square in plan view and shallow in elevation, and conventionally rests upon three feet which normally support the projector upon a flat surface. A projection lens opens from the front and one side of the housing on an axis fixed therewith, and the legs are vertically adjustable to vary the pitch and roll attitude of the unit; yaw attitude being varied by bodily turning the projector unit. It is to be understood that such projectors include the various other features and means necessary thereto, such as a light source, cooling, and electro-mechanical automation means, all of which is state of the art.
Heretofore, projector stands of the type under consideration have provided individually adjustable platforms upon which the aforementioned typical projector rests, the said platform or like framework being adjustable as to pitch, roll and yaw attitude. The required rigid support upon individually adjustable platform-frames is not only space consuming but is weighty and costly. It is a general object of this invention to eliminate supporting platforms or frames of the prior art and to adjustably support the projectors directly upon a stand by utilizing the adjustable leg features common to such projectors for varying pitch and roll attitudes. With the present invention, securement of the projectors to the stand is by means of pitch adjustment means, by roll adjustment means, and by yaw adjustment means, as will be described. Each of these three adjustment means is also a support means, the primary and only support of the projector upon the stand.
State of the art projector stands are characteristically comprised of a heavy base with columnar supports at each of the four corners, and within which there is a bay defined for each projector by a supporting platform or frame which is itself adjustable as to pitch, roll and yaw attitudes. The original adjustment legs of the projector play no part in the adjustment of the platform-frame, the stand and platform-frame being resorted to for all adjustment. The integration of the prior art platform-frame and stand is complicated, weigthy and costly; it is also conducive to looseness and play (backlash) and therefore with loss of accuracy in the ultimate optical projection of images onto the screen. Accordingly, it is an object of this invention to greatly simplify the stand per se, by reducing it to a two legged ladder stabilized by a third leg. A feature of this invention is that each of the three legs accomodates a support adjustment means; one for pitch, one for roll, and one for yaw. In practice, there is a spreader for each bay that accomodates a projector, the two legs of the ladder and said third leg being of light weight tube form each carrying one of the three support adjustment means, for pitch, roll and yaw control. It is also an object of this invention that this three legged ladder-like stand be collapsible for storage and transport within a minimum of space.
Prior art pitch control resorts to forward inclined adjustment of a platform or frame that in turn supports the projector. It is an object of this invention to directly support an original front leg of the projector from a column of the stand, whereby pitch adjustment is attained. Pitch adjustment of the original and typical projector is attained by vertical screw adjustment of a front leg offset to one side of the optical projection axis; in which case the pitch control support means is a fixed bracket carried by a front leg and having a socket to snugly receive a foot of said projector leg. When pitch control is non existant or awkward to use at the said front leg, the pitch control support means is a vertically adjustable bracket carried by said front leg to control the elevation or pitch attitude, the fulcrum therefor existing on an axis line extending between spaced rear leg supports. The receiving socket of the pitch adjustment support means is little or no deeper than the leg-foot, there being no structure beneath this level; no platform or frame.
Prior art roll control resorts to a side to side rocking adjustment of a platform or frame that in turn supports the projector. It is an object of this invention to directly support original and typical rear legs of the projector from spaced columns of the stand, whereby roll adjustment is attained. Roll adjustment of the original and typical projector is attained by vertical screw adjustment at one rear side leg, the other rear side leg remaining fixed or stationary in height. This original typical roll adjustment is a refinement of the projector and is utilized herein through sliding engagement of the leg foot upon a horizontal shelf carried by the spreader that defines the projector bay involved. There is no receiving socket, since the one rear leg foot slides freely upon the shelf. The said one rear leg and supporting shelf and spreader are all at the far rear of the projector and stand therefor; presenting no encumberance beneath the projector being adjustably supported.
Prior art yaw control resorts to a vertical axis turning adjustment of a platform or frame that in turn supports the projector. It is an object of this invention to directly support original and typical rear legs of the projector from spaced columns of the stand, whereby yaw adjustment is attained. There is no yaw adjustment per se in the original typical projector, as it is manually positioned in this respect. Yaw adjustment of the original typical projector is attained by providing lateral screw adjustment of a carriage slideably supported upon the aforesaid spreader to move restrictedly in an arcuate path about the pivot point established by the first mentioned pitch control socket support. Accordingly, the yaw control support means is characterized by a laterally adjustable socket to snugly receive a foot of said projector leg, one of the original typical rear legs of the projector and particularly the fixed or stationary leg at the side opposite the aforementioned roll adjustment leg. The spreader forms a ways upon which the adjusted carriage slides, the said other rear leg and supporting spreader being at the far rear of the projector and stand therefor; presenting no encumberance beneath the projector being adjustably supported.
It is an object of this invention to reserve maximum vertical clearance beneath superimposed projectors, by employing the combination of the aforementioned pitch adjustment support means, the roll adjustment support means and the yaw adjustment support means. By employing these combined means as shown and described, there is nothing between the bottom of one projector and the top of the next underlying projector, and as a result space is maximized and vertical optical centers between the projectors is reduced and minimized as much as is possible commensurate with access to the carousel magazine (as it is shown herein). Accordingly, "keystoning" is minimized, and "perspective control lenses" are optimized. It is also an object that the combined attitude adjustments as disclosed herein are orthogonally related, at right angles of movement with respect to each other.
It is another object of this invention to provide the aforesaid pitch, roll and yaw adjustment-support means integrated in a stand adapted to accomodate a multiplicity of original typical slide projectors, one closely above the other and closely side by side; without disturbing accessibility for magazine replacement and with all active features and controls of the projectors exposed for operation. It is still another object of this invention to provide for unison adjustment of the stand and its multiplicity of projectors, as to pitch, roll and yaw. It is still yet another object of this invention to provide for accuracy in the disposition of multiple projection axes, by providing an anti-deflection structure having inherent rigidity, with self lubricating contacts, and anti-backlash micro-screw adjustment means.